The present invention relates to improvements in vertical truing apparatus, especially those intended for simultaneous truing of the bore and the periphery of annular rings.
Known machines of the kind in question comprise as we know a horizontal crosspiece associated with two fixed uprights supporting one or more heads or grinder-carrier carriages. When it is desired to true pieces of large diameter, the crosspiece has a considerable length. Moreover, the geometric axis of the spindle carrying the grinder is disposed at a rather large distance from the crosspiece since intermediate pieces have to be provided that will allow the pivoting of the grinder-carrier head in a vertical plane. Thus, in known machines there are great difficulties in achieving vertical orientation of the spindle in a precise manner because of the deformations of the different organs from the weight of the carriages.